document.write( "Question 800786: For their field studies in marine ecology, a group of students rented a boat for P360. However, seven students had to withdraw from the group and as a result, the share of each of the remaining students was increased by P21.00. How many students were there in the original group? \n" ); document.write( "
Algebra.Com's Answer #483286 by ankor@dixie-net.com(22740)\"\" \"About 
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For their field studies in marine ecology, a group of students rented a boat for P360.
\n" ); document.write( "However, seven students had to withdraw from the group and as a result, the share of each of the remaining students was increased by P21.00.
\n" ); document.write( " How many students were there in the original group?
\n" ); document.write( ":
\n" ); document.write( "Let x = no. of students in original group
\n" ); document.write( ":
\n" ); document.write( "\"360%2Fx\" = original price per students
\n" ); document.write( "then
\n" ); document.write( "\"360%2F%28%28x-7%29%29\" = actual price per student
\n" ); document.write( ":
\n" ); document.write( "Actual price - original price = 21
\n" ); document.write( "\"360%2F%28%28x-7%29%29\" - \"360%2Fx\" = 21
\n" ); document.write( "multiply by x(x-7) to clear the denominators, resulting in:
\n" ); document.write( "360x - 360(x-7) = 21x(x-7)
\n" ); document.write( "360x - 360x + 2520 = 21x^2 - 147x
\n" ); document.write( "Combine as a quadratic equation
\n" ); document.write( "0 = 21x^2 - 147x - 2520
\n" ); document.write( "simplify, divide by 21
\n" ); document.write( "x^2 - 7x - 120 = 0
\n" ); document.write( "Factors to
\n" ); document.write( "(x-15) (x+8) = 0
\n" ); document.write( "the positive solution is all we want here
\n" ); document.write( "x = 15 students originally
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "See if that checks out, find the cost per student
\n" ); document.write( "360/8 = 45 (actual)
\n" ); document.write( "360/15= 24 (originally)
\n" ); document.write( "------------
\n" ); document.write( "diff: 21
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